Fairbairn U.S. Pat. No. 3,947,653 is concerned with providing a composite laser-RF energy beam to generate high temperatures. The beam is used to form coatings by spraying powders onto workpieces and fusing them.
Banas et al U.S. Pat. No. 4,122,240 is concerned with treating the surface of metal articles by skin melting. A thin surface layer is melted by heating it to a temperature between the melting and vaporization temperatures using a laser as a concentrated energy source. The temperature gradient between the melted and unmelted portion of the article is maximized so that cooling and solidification is extremely rapid when the energy source is removed. This produces unique microstructures.
Yen et al U.S. Pat. No. 4,157,923 is concerned with improving physical properties of a non-allotropic article along a beam affected zone by heat treatment and alloying. A high energy laser beam is passed across the surface area to produce a rapid self-quenching rate which assures a desired precipitate and/or intermetallic compound in the resolidification zone. Alloying is produced in the molten condition.
Serlin U.S. Pat. No. 4,212,900 discloses surface alloying by melting using a laser beam. The alloying material is placed on the substrate surface and a laser beam is directed at it for a predetermined short period of time. The time and beam intensity are cooperatively selected so that the alloying material is melted and alloyed with the substrate.